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Date: 1975 Type: Irrigation Scheme Status: Extant   Click to view large map Coordinates: 30°41'26.62" S 25°45'45.33" E Alt: 1256m

Transcription of information board: The Orange-Fish Tunnel was completed In 1975 and the key is the structure by which water is delivered from Gariep Dam, to the Teebus Spruit and the Great Brak River and from there to the valley of the Great Fish River and the Sundays River continuous enclosed aqueduct in the southern hemisphere and the second longest water supply tunnel in the world. The main purpose of the tunnel is to divert water to the Eastern Cape for irrigation, urban and industrial use. Over 200 000m2 of concrete was used to line the tunnel which has maximum capacity of 54m3/s. The intake tower is situated on the south bank of the Gariep Reservoir at Oviston approximately 19km upstream of the dam wall. Seen from above, the intake tower is shaped like a four-leaf clover with each leaf containing an inlet gate • all at different levels. In this manner, water can be drawn from different levels to help control the water quality. Each of the four inlets can be sealed to allow complete de-watering of the tunnel for routine maintenance.